Rotary valves or feeders generally comprise some form of rotor assembly having a plurality of vanes projecting radially from a shaft which vanes control the movement of material as it passes through the feeder. The rotor is enclosed in a housing having an intake mouth operationally open to a supply of the material being handled, which material flows into those pockets formed by adjacent vanes that are disposed facing the intake. Upon rotor rotation, the filled pockets turn to a position at which they are open to a means for discharging the material, such as a bottom discharge opening, and the material is released from the pocket.
In some feeders, the movement of the material both in and out of the pockets is a gravitational effect, the intake mouth being disposed above the rotor assembly and the discharge means being an opening in the bottom of the rotor housing. The material could instead be discharged by blowing it in a horizontal direction into a discharge tube when the filled pocket turns to a position adjacent such discharge tube. In any instance, the feeder is generally disposed in a line, most often a vertical line with the material flow, and regulates the volume of material passing through the line per unit time.
Materials whose flow can be controlled by such a feeder include solid materials of such suitable form, such as powders, small pellets, and the like, that material movement approaches a resemblence to fluid flow.
When the material is intended for ingestion, particularly human ingestion, such as pharmaceuticals and foodstuff, it is desirable, and at times mandatory, that the surfaces of the feeder that come in contact with the material be free of crevices, cracks, pits, and the like, in which the material or other substances could become entrapped, and therein deteriorate, leading to contamination of material passing through the feeder. In certain applications, such as handling of dairy products, the U.S. Department of Agriculture requires rotary feeders to be free of such crevices, cracks, pits and the like, for approval.
It is an object of the present invention to provide a rotary feeder that is not only easy to disassemble for cleaning its internal parts, but also is free from cracks, crevices, pits, and the like within the rotor housing and thus on all material contact surfaces. It is an object of the present invention to provide such a feeder while maintaining the integrity of the feed passage as to the avoidance of entrance of external contaminants. These and other objects will be made apparent by the disclosure of the invention and the description of the preferred embodiments of the invention.